2nd Grade Teacher Resource Guide Animals of all kinds depend on clean freshwater habitats Theme: during at least some part of their life cycle. Freshwater Flows, Marine Debris, Plastic Pollution Critical Issue: Lesson 1: Life Cycle Art . 3 Contents: Lesson 2: Freshwater Life Cycles . 7 Lesson 3: My Life as a Frog . 20 Lesson 4: If the Water Is Clear . 30 Resources . 35 a division of Embarcadero at Beach St, San Francisco, CA 94133 | 415.623.5300 | aquariumofthebay.org 1 Aquarium of the Bay’s Education and Conservation mission statement: Department’s mission is to promote literacy in ocean and watershed health, climate change issues, and science career development through the lens of critical issues such as sustainable seafood, marine protected areas, marine debris and plastics, climate change and fresh water flows. Aquarium of the Bay thanks the S.D. Bechtel, Jr. Foundation acknowledgements: for their generous support for our K-12 programs and development of this Teacher Resource Guide. 2 Life Cycle Art Enduring Understanding: Frogs, like all animals, have lesson 1 a unique life cycle. Materials Setup: • Frog life cycle 1. Gather frog life cycle materials. materials for 2. Prepare art materials. whiteboard, blackboard, or paper chart • Paper (construction, program outline: computer, watercolor, etc.) What is a life cycle? • Various media • All animals have their own life cycle. (crayons, colored - Some are similar. pencils, watercolor, - Some are different. tempera paint, etc.) • Show students one or more examples of life cycles. - Humans or other animals students are familiar with are good choices for examples. What does the frog life cycle look like? • Frogs, like all animals, have a unique life cycle. Their life cycle has some things in common with those of other animals, but it is also different. • Using the provided life cycle materials, show students the stages of the frog life cycle. Label each one. - Eggs o Laid in freshwater and live inside soft shells while they get ready to hatch - Tadpoles o Live in freshwater, where they breathe water with gills and swim with tails - Froglets o Changing from tadpole that lives in water to adult frog that can live on land 3 program outline continued: - Adult Frogs o Breathe air with lungs and use legs to walk, hop, and swim • Describe each life cycle stage to whatever depth is appropriate for your students. (For more information on each stage, see the “Instructor Background” section of the lesson.) Discuss the idea of metamorphosis • Metamorphosis is when an animal quickly and dramatically changes its body or shape when moving from one life cycle stage to the next. • Some animals, including many insects, go through metamorphosis. • Frogs go through metamorphosis. - When they are tadpoles, frogs have gills to breathe water, a long tail, and no legs. - Adult frogs have lungs to breathe air, no tail, and four legs. - Metamorphosis happens when the tadpole grows lungs, loses its gills, shortens its tail, and grows legs. Create your own artistic representation of the frog life cycle. • Explain that students will be creating their own frog life cycle art. - The art may be creative, but it should include the main characteristics of each life cycle stage. o For example, the tadpole should have a long tail and no legs, the froglet should have short legs and a short tail, and the adult frog should have four developed legs and no tail. o Have the students do each life cycle stage individually. o Once the students have checked the order of the life cycle stages, have the students mount their artwork on a larger piece of paper in the correct order. Student art show • Allow students an opportunity to share their artwork with the class. 4 teacher background: Frogs are a large and diverse group of amphibians that live throughout the world, including in the Bay Area and the San Francisco Bay’s watershed. Both globally and locally, frogs depend on clean freshwater habitats throughout their life cycle. As eggs, tadpoles, and froglets, frogs live in freshwater. Even as adults they must still have access to freshwater. Frogs are also extremely sensitive to pollution in the water, air, and land. Frogs start life as eggs, usually laid in ponds, lakes, or slow-moving streams. Frog eggs are made of a soft, gelatinous material that allows water, nutrients, and oxygen to come in. Tadpoles, or larval frogs, emerge from the eggs. Tadpoles are aquatic animals, breathing water with gills and living in freshwater habitats. Most tadpoles are herbivorous, feeding on planktonic algae, such as diatoms, but a few frog species have carnivorous tadpoles. From the tadpole stage, frogs undergo the process of metamorphosis. During a very short period—only 24 hours in some species—the tadpoles lose their gills and develop lungs with which to breathe air. They also develop legs, lose their tail, and undergo several other changes. The froglets are extremely vulnerable to predation during metamorphosis. Once metamorphosis is complete, the adult frog is free to move between aquatic and terrestrial environments. However, even adult frogs generally live in or near freshwater habitats because they need to stay moist, need these freshwater habitats to reproduce, and may hunt aquatic animals. Adult frogs play an important role in both freshwater and terrestrial food webs, feeding largely on insects and other invertebrates and serving as a food source for many animals, including herons, raccoons, and snakes. 5 glossary: Adult: Final stage of the frog’s life cycle Egg: First stage of the life cycle of many animals, including frogs Froglet: Third stage of frog life cycle; frog during metamorphosis, partway between tadpole and adult; has gills, short tail, and small, undeveloped legs Life Cycle: All the stages of an organism’s life Metamorphosis: Process by which an animal quickly and dramatically changes its body or shape when moving from one life cycle stage to the next Tadpole: Second stage of frog life cycle; frog before beginning metamorphosis; has gills, long tail, and no legs; larval frog 2nd grade standards: California Common Core Standards Visual Arts • 2.2. Demonstrate beginning skill in the use of art media, such as oil pastels, watercolors, and tempera. California Science Content Standards • 2. Plants and animals have predictable life cycles. • 2.b. Students know the sequential stages of life cycles are different for different animals, such as butterflies, frogs, and mice. California Next Generation Science Standards • 2-ESS2-2. Develop a model to represent the shapes and kinds of land and bodies of water in an area. - Develop a model to represent patterns in the natural world. program materials: • Frog life cycle materials for teachers (to be produced and attached) 6 Freshwater Life Cycles Enduring Understanding: Many different kinds of animals live in freshwater during the early part of their lesson 2 life cycle, including frogs, salmon, and dragonflies. Materials Setup: • Life cycle worksheets 1. Make copies of life cycle worksheets. • Pictures of frogs, 2. Find pictures of frogs, salmon, and dragonflies during salmon, and dragonflies various life cycle stages (optional). during various life cycle stages (optional) program outline: What is a life cycle? • All animals have a life cycle. - Some are similar. - Some are different. • Review the idea of life cycles. - Show students one or more examples of life cycles. Humans or other animals students are familiar with are good choices for examples. How do habitats connect to life cycles? • A habitat is an animal home. Animals get everything they need—food, water, and shelter—from their habitat. • Many animals live in the same habitat their whole lives. Some animals live in different habitats during different parts of their life cycle. • We will be learning about some of the animals that live in fresh water for part of their life cycle and other habitats during other parts of their life cycle. “Freshwater Life Cycles” activity • Have students read the narratives about the life cycles of different animals. • Have students answer the question, “Where do I live?” for each part of the worksheet, using the word bank and narratives to help them. 7 program outline continued: Conclusion • Did you notice how all of the animals spent a lot of their life cycle in freshwater? • Even animals we don’t necessarily think of as living in freshwater—like dragonflies—live in freshwater habitats during part of their life cycle. • This is just one of many reasons why it is so important to keep freshwater habitats healthy. 8 teacher background: The Importance of Freshwater Habitats Water is essential to all life on Earth, particularly for those animals that live in or depend on freshwater habitats. Freshwater habitats are crucial for many organisms, including many animals people generally don’t think of as freshwater animals. Many animals live in freshwater for their whole lives, but others who live on land, in the air, or in the sea as adults, including frogs, salmon, and dragonflies, spend the early parts of their life cycle in freshwater. Frogs Frogs are a large and diverse group of amphibians. They live throughout the world, including in the Bay Area and in the San Francisco Bay’s watershed. Both globally and locally, frogs depend on clean freshwater habitats throughout their life cycle. As eggs, tadpoles, and froglets, frogs live in freshwater, and even as adults they must still have access to freshwater. In addition to needed access to freshwater habitats, frogs are also extremely sensitive to pollution in the water, air, and land. Frogs start life as eggs, usually laid in ponds, lakes, or slow-moving streams. Frog eggs are made of a soft, gelatinous material that allows water, nutrients, and oxygen to come in. Tadpoles, or larval frogs, emerge from the eggs.